A study of mine roof of the Pittsburgh coal bed in the Pittsburgh mining district

Author:	Paul, J. W.
Additional Authors:	Plein, Leopold Nicholas,
Year:	1932
Document Type:	USBM
Issuing Agency:	U.S. Bureau of Mines,
SUDOC:	C 22.5:541
Series:	Technical paper / United States. Bureau of Mines ;
Report Number:	541.
Subjects:	Coal mines and mining--Pennsylvania
	Mine timbering
Link:	https://hdl.handle.net/2027/mdp.39015077565623